In many industrial, commercial, and scientific applications, a 360-degree panoramic imaging device is an important device for creating virtual reality content. Generally, the panoramic imaging device may include a plurality of cameras (e.g., wide-angle cameras) to capture images of scenes within 360 degrees. The images of scenes may be further combined into a panoramic image. A number of cameras for the panoramic imaging device depends on how wide-angled the cameras are.
A fisheye camera is a camera intended to create a wide panoramic or hemispherical image, but can produce strong distortion. Fisheye cameras are generally considered to be cameras having field of view (FOV) of at least 180 degrees. That is, not only the view above the horizontal plane where the fisheye camera is disposed is captured, but also the view below the horizontal plane. Therefore, a panoramic imaging device may only need two fisheye cameras to cover a 360-degree panoramic view.
For example, a panoramic imaging device may be used to capture exemplary fisheye images shown in FIG. 1A and FIG. 1B. These images are planar representations of a portion of a sphere. The panoramic imaging device capturing FIG. 1A and FIG. 1B may include a first fisheye camera and a second fisheye camera disposed on a camera rig. As shown in FIG. 1A, the first fisheye camera captures a front hemispherical image for a view in front of the rig. And, as shown in FIG. 1B, the second fisheye camera captures a rear hemispherical image for the view behind the rig. Then, the first and second hemispherical images may be combined, or “stitched,” into a panoramic image. However, directly stitching two hemispherical images (i.e., fisheye images) may be complex and time-consuming.
The methods and devices of this disclosure address the above problem by reducing the complexity of combining two fisheye images into a panoramic image.